Summary: The level and effect of psychosocial risk factors for Alzheimer's may not be the same for African-Americans and Whites. This could mean we need different methods to prevent, diagnose and treat cognitive problems in African-American and White populations. Large-scale studies are needed to confirm this finding.
Alzheimer's is equal opportunity and color blind, right? Well, not exactly. We already know that some risk factors, such as diabetes, are more common among African-Americans. And we know that other risk factors, such as the APOE4 gene variation, may affect African-Americans differently than Whites. But what about psychosocial factors such as emotional states or the strength of social networks?
Dr. Lisa Barnes gave a presentation on "Psychosocial Factors and Cognition in African-Americans and Whites" during the "Psychosocial Issues and Neuropsychology" session at ICAD 2008. Dr. Barnes, who is Associate Professor of Neurological Sciences and Behavioral Sciences at the Rush Alzheimer's Disease Center, sent me some additional information via email to round out my understanding of her work.
The data she presented at ICAD was from participants in three large, ongoing studies at Rush: the Chicago Health and Aging Project, the Memory and Aging Project and the Minority Aging Research Study. In these populations, she and her colleagues (including Dr. Robert Wilson) have found the following differences in the level of psychosocial risk factors between the two races:
- African-Americans are more likely to experience negative emotions or distress than Whites
- African-Americans tend to experience more depression than Whites
- African-Americans report lower levels of social engagement than Whites.
Another study by Dr. Barnes showed that African-Americans with Alzheimer's have a slower rate of cognitive decline than their white counterparts. Perhaps the factors contributing to cognitive decline in African-Americans with Alzheimer's are somewhat different than in Whites. Large scale studies of diverse populations that include both clinical and pathological data are needed to address these questions.
Why does any of this matter? It could mean we need different methods to prevent, diagnose and treat cognitive problems in African-American and White populations. "This has huge public health implications," said Dr. Barnes.
But these findings are also important for each person with memory complaints. "It suggests that there are many factors that may contribute to cognitive impairment," she said, "and that one cannot just measure cognitive performance without considering psychosocial, environmental or cultural factors. These factors may be important even at the very earliest signs of impairment."
It's too early to understand exactly how dementia might be affected by race. "This is a complicated field of study," said Dr. Barnes. "Almost everything we know about Alzheimer's disease and cognitive impairment has been studied in older Whites. There is relatively less information on African-Americans, Hispanics or other people of color. As the nation is becoming more ethnically diverse, and people are living longer, it will be imperative to include all races and ethnicities in our research. We need people of color to volunteer to be in research studies - all kinds of research studies, but particularly those that can link clinical information to pathologic changes in the brain."